You said “plug-ins such as Flash that allow graphics and drag-and-drop in the browser”
Personally I can’t stand Flash because it’s too hard (and expensive) and the documentation is rubbish. It claims to integrate with databases and XML but doesn’t say how. It’s a tool for graphic designers that forces the rest of us to care about their tiny fonts, and before ubiquitous broadband it made a lot of sites (where you just want the information, not the cleverness) unusable. It’s also impossible to spider and index sites properly.
Just my two cents